The subject invention relates to novel copolymers prepared by the interaction of a melt mix of a high molecular weight bisphenol-A polycarbonate polymer, or a low molecular weight bisphenol-A polycarbonate polymer and a high molecular weight diprimary dialcohol polyester polymer, such as a polyethylene arylate, and to the process for their manufacture. The subject invention also provides a process which enables the building of the molecular weight of the combined polymers at lower temperatures than required for the polycarbonate alone.